#练习1
with open('./files/2file.txt','w',encoding='utf-8') as f:
    s = """2023-10-1 晴\n今天学习了Python文件操作"""
    f.write(s)
#练习2
date = input("请输入今天的日期:")
weather = input("记录天气:")
text = input("请编写日记:")
with open('./files/3file.txt','w',encoding='utf-8') as f:
    f.write(f"{date} {weather}\n")
    f.write(f"{text.replace(',','\n')}")
#练习3
with open('./files/bil.txt','r+',encoding='utf-8') as f,open('./files/bil.txt.bak','w',encoding='utf-8') as f_bak:
    #备份
    res = f.read()
    f_bak.write(res)
    #内容删除
    s = ""
    for line in res.split('\n'):
        #如果找不到返回-1
        if line.find('测试') == -1:
            s += line + '\n'
    print(s)
    #回转指针
    f.seek(0)
    #清空内容
    f.truncate()
    #写入新内容
    f.write(s)